Canine influenza is a highly contagious respiratory infection of dogs that is caused by a virus. The canine influenza virus is closely related to the virus that causes equine influenza and it is thought that the equine influenza virus mutated to produce the canine influenza virus.
Two clinical syndromes have been seen in dogs infected with the canine influenza virus—a mild form of the disease and a more severe form that is accompanied by pneumonia. Dogs suffering with the mild form of canine influenza develop a soft, moist cough that persists for 10 to 30 days. Some dogs have a dry cough similar to the “kennel cough” caused by Bordetella bronchiseptica/parainfluenza virus complex. For this reason, canine influenza virus infections are frequently mistaken for “kennel cough.” Dogs with the mild form of influenza may also have a thick nasal discharge, which is usually caused by a secondary bacterial infection. Dogs with the severe form of canine influenza develop high fevers (104° F. to 106° F.) and have clinical signs of pneumonia, such as increased respiratory rates and effort. Pneumonia may be due to a secondary bacterial infection.
Because this is a newly emerging disease, almost all dogs, regardless of breed or age, are susceptible to infection and have no immunity. Virtually all dogs that are exposed to the virus become infected and nearly 80% show clinical signs of disease. Fortunately, most affected dogs have the mild form. Fatal cases of pneumonia resulting from infection with canine influenza virus have been reported in dogs, but the fatality rate (5% to 8%) has been low so far.
The first recognized outbreak of canine influenza in the world is believed to have occurred in racing greyhounds in January 2004 at a track in Florida. From June to August of 2004, outbreaks of respiratory disease were reported at 14 tracks in 6 states (Alabama, Arkansas, Florida, Kansas, Texas, and West Virginia). Between January and May of 2005, outbreaks occurred at 20 tracks in 11 states (Arizona, Arkansas, Colorado, Florida, Iowa, Kansas, Massachusetts, Rhode Island, Texas, West Virginia, and Wisconsin). Infection has also been confirmed in pet dogs in California, Connecticut, Florida, Georgia, Massachusetts, North Carolina, New Jersey, New York, Ohio, Oregon, Pennsylvania, Washington State, and Washington, DC. These cases occurred in animal shelters, humane societies, rescue groups, pet stores, boarding kennels, and veterinary clinics.
A critical aspect of the canine influenza virus situation in dogs is the continued isolation of the virus as it moves through the canine population. While PCR detection of the virus may be useful in the treatment of the patient, simply identifying the presence of the virus does little for understanding how the virus may be changing as it continues to encounter susceptible dogs. Even with the introduction of vaccines, sequence analysis of the isolates will be needed to determine whether canine influenza virus changes as do human influenzas or does it follow the more conservative path of its parent virus equine influenza. Samples need to be forwarded to laboratories that are capable of isolating the virus so that strains are available for genetic analysis.
There is a need for rapid tests for diagnosis of acute canine influenza virus infection. Diagnosis may be confirmed through serologic testing. Antibodies to canine influenza virus may be detected as early as seven days after onset of clinical signs. There is also a need for vaccines or other treatment methods against canine influenza virus.
The present invention is directed to overcoming the deficiencies in the prior art.